International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395 -0056
Volume: 04 Issue: 05 | May -2017
p-ISSN: 2395-0072
www.irjet.net
Analysis of Earthquake Response on RC Structure with and without Base Isolation in Different Plan Shapes Soumya Chandran P1, Megha Vijayan2 1PG
student, Dept of Civil Engineering, Vimal Jyothi Engineering College, Chemperi, Kannur, Kerala, India Professor, Dept of Civil Engineering, Vimal Jyothi Engineering College, Chemperi, Kannur, Kerala, India ---------------------------------------------------------------------***--------------------------------------------------------------------2Asst.
Abstract - Base isolation have become a significant element
Base isolation is a promising technique for controlling the seismic response of structure, during earthquake motions. Seismic isolation and energy dissipating systems are some of the design strategies applied to increase the earthquake resistance of the structures. The period and the damping ratio of the structure isolated from the ground are increased. This, in turn, reduces the earthquake forces on the structure. The increase in damping ratio is a natural characteristic for most isolators. This system dissipates part of the energy created on the structure by the earthquake effect, and thus increases the seismic performance of the structure and of its contents
of a structural system to enhance reliability during an earthquake. It is a technique developed to prevent or reduce damage to building. The principle of seismic isolation is to introduce flexibility in the structure. In this a study of base isolation, with different plan shape G+6 storey with rubber isolation and friction isolation is analyzed by using ETABS. The analysis is done using nonlinear seismic time history data for with and without base isolation. Time history analysis has been performed and performance of RC building is studied with base isolation. The result is compared with and without base isolation structures. Santa Monica is the earthquake that is imposed on the structure .C,H,L and T shapes are analyzed with fixed base, friction isolator and rubber isolator. Key Words: Base Isolation, ETABS, Friction Isolator, Rubber Isolator, Time History Analysis.
There are different types of isolators available, but in this paper rubber isolator and friction isolators are used. Time History Method shall be used on as approximate ground motion and shall be performed by using accepted principles of Dynamics.
1. INTRODUCTION
1.1 Objectives The main objective of this work is
The earthquake resistant structures can be categorized into rigid structures and flexible structures. In rigid structures, the control methods that are applied to withstand extreme loads are basically reducing the inter storey displacement with the help of diagonal bracing, the installation of shear walls and the use of composite materials. In flexible structures, such as base-isolated buildings, the key control approach is to reduce the excitation input with the use of dampers and isolators. When structures are built according to code specifications, they are expected to be damaged during strong earthquakes but to remain standing. This conventional approach to seismic design is not acceptable for critical structures such as hospitals, fire stations, and telecommunications centers. The effective reduction of inter story drift in the floor of base isolation system can ensure the lowest damage to facilities and also human safety.
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Impact Factor value: 5.181
To illustrate the basic concept and behavior of the base isolated structures.
To analyze a building by providing rubber bearing and friction pendulum bearing.
To study and compare base shear, storey drift,time period, displacement with respect to the fixed base and isolated base structure.
To find out the response of RC building subjected to a selected earthquake ground motion by Time History Analysis.
2. MODELING OF STRUCTURE The (G+6) RCC building is located in zone V as per IS: 18932002.It is modeled in ETABS. The (G+6) RC building with different plan shapes is taken and its structural details such as grade of concrete, grade of steel, beam sizes, column sizes and all the other parameters are assumed as per Table 1, 2, and 3.The properties of rubber and friction isolator are given in table 4 and 5.
Seismic isolation systems are more effective when applied to high stiffness, low-rise buildings, owing to their abilities to alter the characteristic of the building from rigid to flexible. The advantage of seismic isolation includes the ability to significantly reduce structural and non-structural damage, to enhance the safety of the building contents, and to reduce seismic design forces. This potential benefits are greatest for stiff structures fixed rigidly to the ground such as low and medium rise building, nuclear power plants, bridges etc.
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